The present disclosure relates to power systems, and, in particular, to microgrid power systems.
A microgrid is an energy distribution network that typically includes one or more Distributed Energy Resources (DERs) and loads. A microgrid may operate in concert with a main power grid and may also operate independently of the main power grid in a mode known as islanded. The connection between a microgrid and the main power grid is typically at a single utility interface point, i.e., one Point-of-Common-Coupling (PCC). This single PCC provides an interface between the microgrid and a feeder of the main power grid. Although some configurations may provide multiple main power grid feeders for supplying power to a microgrid, these configurations are typically designed to connect the multiple main power grid feeders to a single Alternating Current (AC) power bus and this AC power bus serves as the interface to the microgrid at a single PCC. Thus, although multiple main power grid feeders may be available to provide service to a microgrid, the single PCC with the microgrid may reduce the effectiveness and/or the benefits of the redundancy provided through the multiple feeders. For example, although a microgrid typically only uses one main power grid feeder connection under normal operation conditions, when a fault occurs at the PCC or internal to the microgrid, then those loads between the fault and the PCC may be isolated from other potentially available main power grid feeders and may have to rely solely on one or more DERs within the microgrid. Without the ability to efficiently use the multiple main power grid feeders that may be available, a microgrid may need more DERs or DERs with higher power/energy capacities to supply energy and may have reduced reliability and increased costs in delivering power.
In addition, the network topology of a microgrid is generally fixed once it is configured. The static nature of the microgrid network topology, however, may result in inefficiencies, e.g., unnecessary load shedding or power curtailment, due to mismatches between load demands and power generated by the one or more DERs in the microgrid.